An adaptive landscape is a metaphorical representation of the relationship between genotype and fitness or between phenotype and fitness that helps illustrate the multidimensional nature of the evolution of complex systems.

The answer to the question, “what makes organisms the way that they are?”, has two components. The first is the mechanistic or proximate answer, which is based on genetics, cell biology, development, neurobiology, and environmental context. The second is the evolutionary or ultimate answer, which is based on natural selection, mutation, genetic drift, migration, and historical contingency. Fully addressing either of these components requires that they both be carefully investigated and integrated with one another.

To this end, research in the Phillips Lab focuses on understanding the genotype-phenotype map: how genetic information contained within DNA is translated into the whole organism that interacts in the real world. We use the model nematode C. elegans and its relatives to pursue the molecular genetics of this map for traits such as body size, reproductive success, sexual interactions, longevity, and the behavioral response to temperature and chemicals. In collaboration with Robert Kaplan at Reed College, we are also beginning to address these questions in the context of variable ecological environments using frog development as a focal system.

The other side to this equation is understanding how the genetic system itself is molded by the evolutionary process. To investigate this, we use experimental evolution and whole genome analysis within laboratory populations of nematodes to identify the genetic basis of the response to selection, and theoretical approaches to study the evolution of gene interaction systems and suites of coevolving traits.

We are also interested in the role that sexual reproduction and outcrossing play in shaping the pattern of genetic variation and influencing the rate of evolutionary change within natural populations. We have been pursuing these questions by looking at the role of males within C. elegans populations, sexual conflict within its outcrossing relative C. remanei, and the adaptive consequences of genetic exchange within bacterial populations.